Apparatus for sensing pressure using optical waveguide and method thereof

ABSTRACT

Disclosed are an apparatus and a method for sensing pressure using an optical waveguide sensor. The apparatus for sensing pressure using an optical waveguide sensor, includes: a light source radiating light; an optical waveguide panel emitting some of the radiated light outside through a plurality of light transmitting regions previously formed, and changing an amount of totally reflected light according to pressure applied to at least one of the plurality of light transmitting regions; a detector detecting the amount of light; and an analyzer determining intensity and a location of the pressure according to the detected amount of light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean PatentApplication No. 10-2011-0058979 filed in the Korean IntellectualProperty Office on Jun. 17, 2011, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method for sensing pressure accordingto touch, and more particularly, to an apparatus for sensing pressureusing an optical waveguide which may measure a change in an amount oflight passing through the optical waveguide when pressure is applied tothe optical waveguide and sense intensity and a location of the appliedpressure according to the measured change in the amount of the light,and a method thereof.

BACKGROUND ART

In general, a touch pad is an input device that may sense a location ofa contact point by contacting another object such as a finger or a penon a pad location of a point corresponding to a screen of a displaydevice. In recent years, the touch pad has been used as a representativemethod instead of a mouse of a notebook computer. A touch screen is adevice that a user contacts a picture or a character visually displayedon a screen by hand or with a pen to perform a command by attaching atransparent sensor having the same size as that of a display device to ascreen coordinate and a contact point coordinate to correspond to eachother.

The types of the foregoing touch panel and touch screen may beclassified for each medium sensing a contact signal. There are aresistive type, a surface acoustic wave (SAW) type, a capacitive type,and the like as representative types of the touch pad or the touchscreen.

In a resistive type touch screen panel, insulation bars are providedbetween a glass or transparent plastic plate and a polyester film usinga resistive material at predetermined distance such that the glass ortransparent plastic plate and the polyester film do not contact in sucha way that the resistive material is coated on the glass or transparentplastic plate and the polyester film is covered thereon. When the usertouches the resistive type touch screen panel, a resistance value variesand an applied voltage also varies due to a physical change in theinsulation bars. A contact location is recognized according to thevariation in the applied voltage.

The SAW type touch screen panel includes a transmitter, a reflector, anda receiver. The transmitter generates an ultrasonic wave and is attachedto one corner of glass. The reflector reflects a sound wave and isspaced apart from the transmitter by a predetermined distance. Thereceiver is attached to another side of the reflector. When a panelcontacts an object such as a finger preventing the sound wave, someultrasonic wave is absorbed. The SAW type touch screen panel uses amethod of calculating a location where the change occurs andsimultaneously recording a contact location.

In a capacitive type touch screen, when both sides of glass are coatedwith a transparent special conductive metal and a voltage is applied tofour corners of a screen, a high frequency is generated on a surface ofthe touch screen. In this case, if a conductive object such as a user'sfinger contacts on the capacitive type touch screen, a high frequencycomponent become low. Such digital data is analyzed by a controller tofind out a contact location. The method is not influenced by externalfactors and a panel has high transparency and thus is the mostfrequently used technology.

An infrared type touch screen uses straight attribute of light, and is atechnology using an attribute that is blocked and is not advanced whenthere is an obstacle. In a basic structure of a panel, a plurality ofinfrared light emitting diodes being an emission device and aphoto-transistor being a receiving device are disposed to face eachother, and an optical grating frame is made and mounted around a frontcover of a monitor. An object such as a finger touches the infrared typetouch screen, because light is blocked and is not sensed by aphoto-transistor of an opposite side, a touched location of a cell isrecognized.

Because only on/off of an existing touch pad is sensed based on an inputsignal, whether an operation is performed suited to the intention of auser can be known by only a change in a corresponding picture or button.Accordingly, because an error with respect to a desired operation of theuser can be appreciated according to presence of a function operation,delay occurs for some time. When the touch pad is used by only on/offinput as described above, sensitivity of the touch pad may not beadjusted, operation erroneously performed cannot be prevented when a keyis strongly input.

An existing touch screen touches a screen based on a screen, namely, apanel to recognize a location, and may perform a multi-touch function, adrag function, and the like in some cases. However, the multi-touchfunction, the drag function, and the like are performed by a methodcapable of being used in a plane, and thus it is difficult to implementa previous resolution and precision in an irregular side. As in thetouch pad, because the existing touch screen recognizes only on/offinput, namely, touch, the touch screen may cause an erroneous operationof desired input.

Such problems occur because the touch screen cannot recognize pressurewhich the user applies.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide an apparatusfor sensing pressure using an optical waveguide which may measure achange in an amount of light passing through the optical waveguide whenpressure is applied to the optical waveguide and sense intensity and alocation of the pressure according to the measured change in the amountof light, and a method thereof.

The present invention further provides an apparatus for sensing pressureusing an optical waveguide which may sense the intensity of pressure byusing a change in amount of light passing through the optical waveguideand sense intensity and a location of the pressure so as to allow a userto recognize the sensed intensity of pressure, and a method thereof.

However, an object of the present invention is not limited to theabove-mentioned matters, and other non-mentioned objects will becomeapparent to those skilled in the art based on the following explanation.

An exemplary embodiment of the present invention provides an apparatusfor sensing pressure using an optical waveguide sensor, including: alight source radiating light; an optical waveguide panel emitting someof the radiated light to the outside through a plurality of lighttransmitting regions previously formed, and changing an amount oftotally reflected light according to pressure applied to at least one ofthe plurality of light transmitting regions; a detector detecting theamount of light; and an analyzer determining intensity and a location ofthe pressure according to the detected amount of light.

The optical waveguide panel may include: a first cladding layer; a corelayer formed in an upper portion of the first cladding layer in agrating pattern, and totally reflecting and transmitting the lightradiated from the light source; and a second cladding layer formed in anupper portion of the first cladding layer on which the core layer isformed, and having the light transmitting region where holes are formedat a predetermined interval at the upper portion of the core layer, andsome of the light passing through the core layer are emitted to theoutside through the formed holes.

The optical waveguide panel may include: a first cladding layer; a corelayer formed in an upper portion of the first cladding layer in agrating pattern, and having the light transmitting region on which thefirst cladding layer has a bent shape at a predetermined interval, andsome of light radiated from the light source are emitted to the outside;and a second cladding layer formed in an upper portion of the firstcladding layer on which the core layer is formed.

The optical waveguide panel may include: a first cladding layer; a corelayer formed in an upper portion of the first cladding layer in agrating pattern, and totally reflecting and transmitted to the lightradiated from the light source; a second cladding layer formed in anupper portion of the first cladding layer on which the core layer isformed; and a photo elastic layer inserted into the second claddinglayer at a predetermined interval and emitting some of the light passingthrough the core layer to the outside.

The photo elastic layer may use a photo elastic material having arefraction index different from that of the second cladding layer, and aside of the photo elastic layer may contact the core layer.

The optical waveguide panel includes an electric elastic layer that maybe formed in a lower portion of the first cladding layer, and receivingan electric signal according to the intensity of the pressure applied tothe light transmitting region such that physical properties in theelectric elastic layer vary.

When the electric elastic layer receives the electric signal, thephysical properties in the electric elastic layer may vary left andright.

When the electric elastic layer receives the electric signal, thephysical properties in the electric elastic layer may vary upward anddownward.

The more the amount of light is, the higher the intensity of thepressure may be, and the less the amount of light is, the lower theintensity of the pressure may be.

Another exemplary embodiment of the present invention provides anapparatus for sensing pressure using an optical waveguide sensor,including: a light source radiating light; an optical waveguide panelemitting some of the radiated light to the outside through a pluralityof light transmitting regions previously formed, and changing an amountof light totally reflected according to pressure applied to at least oneof the plurality of light transmitting regions; a detector detecting theamount of light; and an analyzer determining intensity and a location ofthe pressure according to the detected amount of light, wherein theoptical waveguide panel receives an electric signal from the analyzeraccording to the intensity of the pressure, and physical properties inthe optical waveguide panel vary in a region to which the pressure isapplied.

When the optical waveguide panel receives the electric signal, thephysical properties in the optical waveguide panel may vary left andright.

When the optical waveguide panel receives the electric signal, thephysical properties in the optical waveguide panel may vary upward anddownward.

The more the amount of light is, the higher the intensity of thepressure may be, and the less the amount of light is, the lower theintensity of the pressure may be.

Yet another exemplary embodiment of the present invention provides amethod for sensing pressure using an optical waveguide sensor,including: radiating light to an optical waveguide panel to emit some ofthe light outside through a plurality of light transmitting regionspreviously formed; detecting an amount of light changed according topressure applied to at least one of the plurality of light transmittingregions; and determining intensity and a location of the pressureaccording to the detected amount of the light.

The method may further include applying an electric signal to a regionto which pressure of the optical waveguide panel is applied according tothe intensity of the pressure to vary physical properties in the region.

The varying of the physical properties may include applying an electricsignal to a region to which pressure of the optical waveguide panel isapplied according to the intensity of the pressure to vary physicalproperties in a left side and a right side of the region.

The varying of the physical properties may include applying an electricsignal to a region to which pressure of the optical waveguide panel isapplied according to the intensity of the pressure to vary physicalproperties in up and down directions of the region.

The more the amount of light is, the higher the intensity of thepressure may be, and the less the amount of light is, the lower theintensity of the pressure may be.

According to exemplary embodiments of the present invention, it ispossible to measure a change in an amount of light passing through theoptical waveguide when pressure is applied to the optical waveguide andto sense intensity and a location of the applied pressure according tothe measured change in the amount of light, thereby more preciselydetecting the intensity and location of the pressure.

It is also possible to sense the intensity of the pressure by using achange in an amount of light passing through the optical waveguideaccording to the applied pressure to allow a user to recognize thesensed pressure intensity, thereby controlling the pressure intensity.

It is also possible to sense the intensity of the pressure by using achange in an amount of light passing through the optical waveguideaccording to the applied pressure to allow a user to recognize thesensed intensity of the pressure, thereby implementing various userinterfaces.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary diagram illustrating an apparatus for sensingpressure according to an exemplary embodiment of the present invention.

FIGS. 2A, 2B and 2C are first exemplary diagrams illustrating aprinciple for sensing pressure according to the exemplary embodiment ofthe present invention.

FIGS. 3A, 3B and 3C are second exemplary diagrams illustrating aprinciple for sensing pressure according to the exemplary embodiment ofthe present invention.

FIGS. 4A, 4B and 4C are third exemplary diagrams illustrating aprinciple for sensing pressure according to the exemplary embodiment ofthe present invention.

FIG. 5 is an exemplary diagram illustrating another configuration of anoptical waveguide panel according to the exemplary embodiment of thepresent invention.

FIGS. 6A, 6B and 6C are exemplary diagrams illustrating a principle forreturning a physical stimulation according to the exemplary embodimentof the present invention.

FIG. 7 is an exemplary diagram illustrating a process of processing aphysical stimulation according to the exemplary embodiment of thepresent invention.

FIG. 8 is an exemplary diagram illustrating a method for sensingpressure according to an exemplary embodiment of the present invention.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the present invention as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Hereinafter, an apparatus and a method for sensing pressure using anoptical waveguide according to exemplary embodiments of the presentinvention will be described in detail with reference to the accompanyingdrawings, namely, FIGS. 1 to 8. The exemplary embodiments of the presentinvention will be described in detail based on parts necessary tounderstand operations and functions of the present invention. Throughoutthe specification, in giving reference numerals to elements of eachdrawing, like reference numerals refer to like elements even though likeelements are shown in different drawings.

An exemplary embodiment of the present invention suggests an approachwhich may measure a change in an amount of light passing through anoptical waveguide when pressure is applied to the optical waveguide andsense intensity and a location of the applied pressure according to themeasured change in the amount of light, and may allow a user torecognize the sensed intensity of the pressure, and a method thereof.Here, the optical waveguide refers to an optical fiber designed suchthat an optical signal is transferred.

FIG. 1 is an exemplary diagram illustrating an apparatus for sensingpressure according to an exemplary embodiment of the present invention.

As shown in FIG. 1, the apparatus for sensing pressure according to theexemplary embodiment of the present invention may include a first lightsource 110, a second light source 120, an optical waveguide panel 200, afirst detector 310, a second detector 320, and an analyzer 400, as auser input device for sensing pressure according to touch. For example,the user input device may be a concept generally including a key pad, atouch pad, a touch screen, and the like.

The first light source 110 and the second light source 120 may radiatelight to the optical waveguide panel 200, respectively. For example, thefirst light source 100 may radiate the light in a transverse directionof the optical waveguide panel 200, and the second light source 120 mayradiate the light in a longitudinal direction of the optical waveguidepanel 200.

The optical waveguide panel 200 may include a core layer 210transmitting light and a cladding layer 220 surrounding the core layer210 and preventing light from being emitted to the outside of the corelayer 210. Here, the core layer 210 and the cladding layer 220 havedifferent refraction indexes such that the core layer 210 totallyreflects and transmits the light. The core layer 210 may be formed in agrating pattern.

The optical waveguide panel 200 may transmit the light, and an amount ofthe transmitted light is changed according to intensity of pressureapplied from the user. Particularly, the optical waveguide panel 200radiates some of the light outside through a plurality of lighttransmitting regions previously formed, and changes an amount of totallyreflected light according to pressure applied to at least one of theplurality of light transmitting regions.

That is, the higher the intensity of the pressure is, the more theamount of light passing through the optical waveguide panel 200 is. Thelower the intensity of the pressure is, the less the amount of lightpassing through the optical waveguide panel 200 is.

The light transmitting region may be implemented in various forms, andseveral examples thereof will be described below.

The optical waveguide panel 200 may return a physical stimulation to theuser according to a change in the amount of light. Here, the physicalstimulation may refer to tactile indicating whether a user contacts orthe intensity of the touch. For example, through the function ofreal-time returning the physical stimulation, functions of various userinterfaces, for example, a key pad, a multi-key pad, a touch screen, amouse, and the like may be implemented.

The first detector 140 may detect an amount of light passing through aplurality of core layers arranged parallel with each other atpredetermined intervals in a transverse direction, and the seconddetector 150 may detect an amount of light passing through a pluralityof core layers arranged parallel with each other at predeterminedintervals in a longitudinal direction. Here, a photo transistor or thelike may be used as the first detector 140 and the second detector 150.

The analyzer 160 may determine a touched intensity and a touchedlocation of the pressure based on the detected amount of the light. Theanalyzer 160 may apply an electric signal to the optical waveguide panelto apply a physical stimulation to the user according to the intensityof the pressure applied to the light transmitting region.

FIGS. 2A, 2B and 2C are first exemplary diagrams illustrating aprinciple for sensing pressure according to the exemplary embodiment ofthe present invention.

FIGS. 2A, 2B and 2C are cross-sectional views of the optical waveguidepanel 200 according an exemplary embodiment of the present invention.The optical waveguide panel 200 may include a first cladding layer 221,a core layer 210 formed in an upper portion of the first cladding layer221, a second cladding layer 222 formed in an upper portion of the corelayer 210, and the like.

The second cladding layer 222 has a light transmitting region 223 awhere apertures or holes are formed at a predetermined interval at upperportions of the core layer 210, and some of light passing through thecore layer 210 are emitted to the outside through the formed holes. Inthis case, a distance between the holes may be formed to have 1 mm orless.

In FIG. 2A, if the user does not apply pressure to the optical waveguidepanel 200 from the outside, some of the light passing through the corelayer 210 are emitted to the outside through all the formed holes.

In FIG. 2B, if the user applies first pressure to a predetermined hole,some of the light passing through the core layer 210 are emitted to theoutside through a hole to which the pressure is applied. However,because the amount of light emitted to the outside in FIG. 2B is reducedin comparison with the case of FIG. 2A, an amount of totally reflectedand transmitted light is increased. In FIG. 2C, if the user appliessecond pressure higher than the first pressure hole, an external path ofa hole is blocked such that the light passing through the core layer isnot emitted to the outside.

In this case, intensity of the first pressure and intensity of thesecond pressure are set according to the amount of light.

As described above, the amount of light passing through the core layeris changed according to intensity of pressure applied to the hole. Thatis, the higher the pressure intensity applied to the hole is, the morethe amount of light passing through the core layer is. The lower thepressure intensity applied to the hole is, the less the amount of lightpassing through the core layer is.

FIGS. 3A, 3B and 3C are second exemplary diagrams illustrating aprinciple for sensing pressure according to the exemplary embodiment ofthe present invention.

FIGS. 3A, 3B and 3C are cross-sectional views of the optical waveguidepanel according an exemplary embodiment of the present invention. Theoptical waveguide panel may include a first cladding layer 221, a corelayer 210 formed in an upper portion of the first cladding layer 221, asecond cladding layer 222 formed in an upper portion of the core layer210, and the like.

The core layer 210 has a light transmitting region 223 b where the firstcladding layer 221 has a convex or bent shape at a predeterminedinterval, and some of light are emitted to the outside at a bent shape.Here, the bent shape may be implemented in various shapes such as atriangle shape, a circle, an ellipse, or a square. In this case, adistance between the bent shapes may be formed to have 1 mm or less.

In FIG. 3A, if the user does not apply pressure from the outside, someof the light passing through the core layer 210 are emitted to theoutside through all the bent shapes. In this case, the light is emittedto the first cladding layer 221 or the second cladding layer 222 throughthe bent shapes.

In FIG. 3B, if the user applies first pressure in a predetermined bentshape, some of the light passing through the core layer 210 are emittedto the outside through a bent shape to which pressure is applied.However, because the amount of light emitted to the outside in FIG. 3Bis reduced in comparison with the case of the FIG. 3A, an amount oftotally reflected and transmitted light is increased. In FIG. 3C, if theuser applies second pressure higher than the first pressure in apredetermined bent shape, the bent shape is spread in a straight shapesuch that the light passing through the core layer 210 is not emitted tothe outside.

As described above, an amount of light passing through the core layer ischanged according to intensity of the pressure applied to the bentshape. That is, the higher the intensity of the pressure applied to thebent shape is, the more the amount of the light passing through the corelayer is. The lower the intensity of the pressure applied to the bentshape is, the less the amount of the light passing through the corelayer is.

FIGS. 4A, 4B and 4C are third exemplary diagrams illustrating aprinciple for sensing pressure according to the exemplary embodiment ofthe present invention.

FIGS. 4A, 4B and 4C are cross-sectional views of the optical waveguidepanel 200 according an exemplary embodiment of the present invention.The optical waveguide panel 200 may include a first cladding layer 221,a core layer 210 formed in an upper portion of the first cladding layer221, a second cladding layer 222 formed in an upper portion of the corelayer 210, and a photo elastic layer 223 c.

The photo elastic layer 223 c is inserted into the second cladding layer222 at a predetermined interval as a light transmitting region 223 c. Aside of the photo elastic layer 223 c is formed to contact the corelayer 210, and the photo elastic layer 223 c emits some of the lightpassing through the core layer 210 to the outside. In this case, thephoto elastic layer 223 c uses a photo elastic material having arefraction index different from that of the second cladding layer 222. Adistance between the photo elastic layers 223 c may be formed to have 1mm or less.

In FIG. 4A, if the user does not apply pressure from the outside, someof the light passing through the core layer are emitted to the outsidethrough all the formed photo elastic layers.

In FIG. 4B, if the user applies first pressure to a predetermined photoelastic layer, some of the light passing through the core layer areemitted to the outside through the photo elastic layer to which pressureis applied. Because the amount of light emitted to the outside in FIG.4B is reduced in comparison with the case of the FIG. 4A, an amount oftotally reflected and transmitted light is increased.

In FIG. 4C, if the user applies second pressure higher than the firstpressure to a predetermined photo elastic layer, an external path of ahole is blocked such that the light passing through the core layer isnot emitted to the outside.

As described above, an amount of light passing through the core layer ischanged according to intensity of the pressure applied to the photoelastic layer. That is, the higher the intensity of the pressure appliedto the photo elastic layer is, the more the amount of the light passingthrough the core layer is. The lower the intensity of the pressureapplied to the photo elastic layer is, the less the amount of the lightpassing through the core layer is.

FIG. 5 is an exemplary diagram illustrating another configuration of anoptical waveguide panel according to the exemplary embodiment of thepresent invention.

FIG. 5 is a partially cross-sectional view of the optical waveguidepanel according to an exemplary embodiment of the present invention. Theoptical waveguide panel may include a first cladding layer 221, a corelayer 210 formed in an upper portion of the first cladding layer 221, asecond cladding layer 222 formed in an upper portion of the core layer210, and an electric elastic layer 223 c.

The construction of emitting some of light transmitting a core layer toan outside is identical to that shown in FIGS. 2 to 4, and thus thedescription thereof is omitted.

The electric elastic layer 224 is formed in a lower portion of the firstcladding layer 221. When the electric elastic layer 224 receives anelectric signal according to the intensity of the pressure applied to alight transmitting region, physical properties in the electric elasticlayer 224 vary, that is, the electric elastic layer 224 is contracted orexpanded. That is, because a contracted degree of the electric elasticlayer 224 is changed according to intensity of pressure, every time thepressure is applied, the electric elastic layer 224 returns a physicalstimulation to a user.

In this case, physical properties in the electric elastic layer 224 varyin left and right directions or up and down directions.

FIGS. 6A, 6B and 6C are exemplary diagrams illustrating a principle forreturning a physical stimulation according to the exemplary embodimentof the present invention.

As shown in FIG. 6A, if the user does not apply pressure to a lighttransmitting region, some of the light passing through the core layerare emitted to the outside through all the formed photo elastic layers,and physical properties in the electronic elastic layer do not vary.

In FIG. 6B, if the user applies first pressure to a predetermined lighttransmitting region, some of the light passing through the core layerare emitted to the outside through a light transmitting region to whichthe pressure is applied. However, because the amount of light emitted tothe outside in FIG. 6B is reduced in comparison with the case of theFIG. 6A, an amount of totally reflected and transmitted light isincreased. An electric signal corresponding to the first pressure isapplied to the electric elastic layer 224 such that physical propertiesin the electric elastic layer 224 vary, that is, the electric elasticlayer 224 is significantly contracted upward and downward.

In FIG. 6C, if the user applies second pressure higher than the firstpressure to a predetermined light transmitting region, an external pathof the light transmitting region is blocked such that the light passingthrough the core layer is not emitted to the outside. An electric signalcorresponding to the second pressure is applied to the electric elasticlayer such that the physical properties in the electric elastic layervary, that is, the electric elastic layer is contracted upward anddownward larger than that of FIG. 6A.

FIG. 7 is an exemplary diagram illustrating a process of processing aphysical stimulation according to the exemplary embodiment of thepresent invention.

FIG. 7 shows in detail a process of applying how to feedback if pressurecorresponding to a desired operation is applied using an input device.

First, when there is no pressure, the input device sets a variablePressDownState to zero (PressDownState=0) (S710). If the pressure isapplied, the input device determines whether a magnitude of the appliedpressure is lower than a level 1 (S720). When the magnitude of theapplied pressure is not lower than the level 1, the input device maydetermine whether the magnitude of the applied pressure is level 1(S730).

That is, when the user increases the pressure applied to an upper partof the input device constant so that the magnitude of the pressurereaches first pressure or the level 1, a physical stimulation or tactilefeedback is generated (S740). In this case, when the magnitude of thepressure reaches level 1 using the variable PressDownState, a tactileoutput is generated only once. That is, before the pressure is appliedagain in a state that pressure lower than or equal to the level 1 isapplied, generated tactile feedback is not regenerated.

Next, in case where there is no input, if pressure at level 1 is appliedin a state that the variable PressDownState is set to zero(PressDownState=0), the variable PressDownState is set to 1(PressDownState=1) (S750).

Subsequently, if the pressure is continuously applied, the input devicedetermines whether the magnitude of the pressure is equal to or higherthan level 1 (S760). When the magnitude of the pressure is equal to orhigher than level 1, the input device may determine whether themagnitude of the pressure is at level 2 (S770).

That is, when the magnitude of the pressure exceeds level 1 and reacheslevel 2, the user generates a new tactile output (S780). In this case, atactile output when the pressure reaches level 2 provides anotherpattern having intensity higher than intensity or having the stimulationnumber greater than the stimulation number when the pressure reacheslevel 1 such that a user may intuitively know the applied pressure byoneself. In this case, as described above, when the pressure reacheslevel 2, a moment tactile output is generated only once.

Next, if pressure of level 2 is applied in a state that the variablePressDownState is set to 1 (PressDownState=1) at pressure of level 1,the variable PressDownState is set to 2 (PressDownState=2) (S790).

In this case, before the magnitude of the pressure is reduced to level 2or less and then is increased, for example, before the magnitude of thepressure is reduced to level 1 and then is increased to level 2, atactile output corresponding to level 2 is not generated. In this case,only when the pressure is continuously increased using a variablePressDownState in a previous state, the tactile output is generated.

FIG. 8 is an exemplary diagram illustrating a method for sensingpressure according to an exemplary embodiment of the present invention.

As shown in FIG. 8, an input device according to an exemplary embodimentof the present invention may radiate light to an optical waveguidepanel, and radiate light in a transverse direction and a longitudinaldirection of the optical waveguide panel, respectively (S810).

Next, the input device may detect an amount of light passing through theoptical waveguide panel (S820), and determine intensity and a locationof pressure according to the detected amount of the light (S830). Here,the intensity of the pressure may be divided into first pressure andsecond pressure, and may be divided into two or more as needed.

Next, the input device may generate an electric signal corresponding tothe intensity of pressure, and apply the generated electric signal to aregion to which the pressure of the optical waveguide panel is appliedbased on the location of the pressure (S840). That is, the input devicemay apply a first electric signal to a region to which pressure isapplied according to first pressure and a second electric signal to aregion to which the pressure is applied according to second pressure, soas to transfer different physical stimulations to a user according tothe intensity of the pressure.

As described above, the apparatus and the method for sensing pressureusing an optical waveguide according to the exemplary embodiments of thepresent invention have been described and illustrated in the drawingsand the specification. The exemplary embodiments were chosen anddescribed in order to explain certain principles of the invention andtheir practical application, to thereby enable others skilled in the artto make and utilize various exemplary embodiments of the presentinvention, as well as various alternatives and modifications thereof. Asis evident from the foregoing description, certain aspects of thepresent invention are not limited by the particular details of theexamples illustrated herein, and it is therefore contemplated that othermodifications and applications, or equivalents thereof, will occur tothose skilled in the art. Many changes, modifications, variations andother uses and applications of the present construction will, however,become apparent to those skilled in the art after considering thespecification and the accompanying drawings. All such changes,modifications, variations and other uses and applications which do notdepart from the spirit and scope of the invention are deemed to becovered by the invention which is limited only by the claims whichfollow.

1. An apparatus for sensing pressure using an optical waveguide sensor,the apparatus comprising: a light source radiating light; an opticalwaveguide panel emitting some of the radiated light outside through aplurality of light transmitting regions previously formed, and changingan amount of totally reflected light according to pressure applied to atleast one of the plurality of light transmitting regions; a detectordetecting the amount of the light; and an analyzer determining intensityand a location of the pressure according to the detected amount oflight.
 2. The apparatus of claim 1, wherein the optical waveguide panelincludes: a first cladding layer; a core layer formed in an upperportion of the first cladding layer in a grating pattern, and totallyreflecting and transmitted to the light radiated from the light source;and a second cladding layer formed in an upper portion of the firstcladding layer on which the core layer is formed, and having the lighttransmitting region where holes are formed at a predetermined intervalat the upper portion of the core layer, and some of the light passingthrough the core layer are emitted to the outside through the formedholes.
 3. The apparatus of claim 1, wherein the optical waveguide panelincludes: a first cladding layer; a core layer formed in an upperportion of the first cladding layer in a grating pattern, and having thelight transmitting region where the first cladding layer has a bentshape, and some of the light radiated from the light source are emittedfrom the light transmitting region to the outside; and a second claddinglayer formed in an upper portion of the first cladding layer on whichthe core layer is formed.
 4. The apparatus of claim 1, wherein theoptical waveguide panel includes: a first cladding layer; a core layerformed in an upper portion of the first cladding layer in a gratingpattern, and totally reflecting and transmitted to the light radiatedfrom the light source; a second cladding layer formed in an upperportion of the first cladding layer on which the core layer is formed;and a photo elastic layer inserted into the second cladding layer at apredetermined interval and emitting some of the light passing throughthe core layer to the outside.
 5. The apparatus of claim 4, wherein thephoto elastic layer uses a photo elastic material having a refractionindex different from that of the second cladding layer, and a side ofthe photo elastic layer contacts the core layer.
 6. The apparatus ofclaim 2, wherein the optical waveguide panel includes an electricelastic layer formed in a lower portion of the first cladding layer, andreceiving an electric signal according to the intensity of the pressureapplied to the light transmitting region such that physical propertiesin the electric elastic layer vary.
 7. The apparatus of claim 6, whereinwhen the electric elastic layer receives the electric signal, thephysical properties in the electric elastic layer vary left and right.8. The apparatus of claim 6, wherein when the electric elastic layerreceives the electric signal, the physical properties in the electricelastic layer vary upward and downward.
 9. The apparatus of claim 1,wherein the more the amount of light is, the higher the intensity of thepressure is, and the less the amount of light is, the lower theintensity of the pressure is.
 10. An apparatus for sensing pressureusing an optical waveguide sensor, the apparatus comprising: a lightsource radiating light; an optical waveguide panel emitting some of theradiated light to outside through a plurality of light transmittingregions previously formed, and changing an amount of light totallyreflected according to pressure applied to at least one of the pluralityof light transmitting regions; a detector detecting the amount of light;and an analyzer determining intensity and a location of the pressureaccording to the detected amount of light, wherein when the opticalwaveguide panel receives an electric signal from the analyzer accordingto the intensity of the pressure, and physical properties in the opticalwaveguide panel vary in a region to which the pressure is applied. 11.The apparatus of claim 10, wherein when the optical waveguide panelreceives the electric signal, the physical properties in the opticalwaveguide panel vary left and right.
 12. The apparatus of claim 10,wherein when the optical waveguide panel receives the electric signal,the physical properties in the optical waveguide panel vary upward anddownward.
 13. The apparatus of claim 10, wherein the more the amount oflight is, the higher the intensity of the pressure is, and the less theamount of light is, the lower the intensity of the pressure is.
 14. Amethod for sensing pressure using an optical waveguide sensor, themethod comprising: emitting light to an optical waveguide panel to emitsome of the radiated light outside through a plurality of lighttransmitting regions previously formed, detecting an amount of lightchanged according to pressure applied to at least one of the pluralityof light transmitting regions; and determining intensity and a locationof the pressure according to the detected amount of light.
 15. Themethod of claim 14, further comprising: applying an electric signal to aregion to which pressure of the optical waveguide panel is appliedaccording to the intensity of the pressure to vary physical propertiesin the region.
 16. The method of claim 15, wherein the varying of thephysical properties includes applying an electric signal to a region towhich pressure of the optical waveguide panel is applied according tothe intensity of the pressure to vary physical properties at a left sideand a right side of the region.
 17. The method of claim 15, wherein thevarying of the physical properties includes applying an electric signalto a region to which pressure of the optical waveguide panel is appliedaccording to the intensity of the pressure to vary physical propertiesin up and down directions of the region.
 18. The method of claim 14,wherein the more the amount of light is, the higher the intensity of thepressure is, and the less the amount of light is, the lower theintensity of the pressure is.